1. Field of the Invention
This invention relates to a process and apparatus for closing one end of a tubular bar, which is filled with flowable solids. Such tubular bars are used to make spacer frames for insulating glass. The tubular bars consist of aluminum or steel and are filled with a readily flowable, granular desiccant and are then processed further to form closed frames in that the bars are bent and/or are interfitted by means of connectors, which are fitted in alternation into the ends of the tubular bars. Perforation holes are usually provided on that side of the tubular bars which in the complete insulating glass pane faces the interior space of the insulating glass pane. Through said perforations the desiccant contained in the tubular bar can absorb and bind moisture from the interior of the insulating glass pane.
2. Description of the Prior Art
To prevent a flow of the desiccant out of the tubular bars during the process steps for making the spacer frames. The tubular bars must be closed at their ends. This has usually been effected in that a foamed rubber plug has been inserted into each end of each tubular bar. To retain the foamed rubber plugs in the tubular bars, said plugs are initially thicker than the tubular bars and are compressed with the fingers and when compressed are pushed into the tubular bars, where they tend to expand so that they are sufficiently retained. It is also known to insert into one of the two ends of a tubular bar at the beginning a connector which will be required in any case for the formation of a closed frame and to insert a foamed rubber plug only into the opposite end of the tubular rod.
The use of foamed rubber plugs to seal the tubular bars has the disadvantage that the plugs may easily be chafed and caught at edges, corners and burrs of the tubular bars so that portions of the foamed rubber plugs can be worn off or torn off. This is undesirable because such detached foamed rubber particles may deposit on the outside of the spacer frame or may contaminate the work-place. Besides, foamed rubber plugs cannot easily be used in an automatic process of closing tubular bars.